Memory systems are frequently defined by specifications such as the DDR (double data rate) Specification. The “DDR Specification” refers to any of the specifications that define DDR technology including, for example, The DDR2 Specification published by the Joint Electron Device Engineering Council (JEDEC). The DDR Specification calls for very tight jitter and timing specifications. Meeting these jitter and timing specifications is becoming more difficult because the IO (input/output) frequencies of DDR memory systems is increasing. The majority of the jitter and timing error is due to power supply noise.